Treating jute fibers



Patented Feb. 18, 1947 TREATING JUTE FIBERS Roger Wallach, deceased, late of Briarcliff Manor,

N. Y., by George Hills, executor, New

Rochelle, N. Y., assignor, by mesne assignments, to American Viscose Corporation, Wilmington, Del., a corporation of Delaware No Drawing. Application April 23, 1942, Serial No. 440,210. In Great Britain June 29, 1938 Claims.

This invention relates to the treatment of textile material, and more particularly to a process and composition for the treatment of jute textiles used in the manufacture of sacks, bags, packages, container liners and the like and to correlated improvements in the articles produced.

Textiles, in particular when made of jute fibres, often have superficial fibres loosely attached to their surface and as these fibres are non-felting and wiry in character they have a tendency to become loosened and detached from the textile during use of the material. When such materials are made up into sacks or the like, the superficial fibres tend to shed into the contents of the sack.

A prior method of treating such textiles con sists in depositing cellulose xanthate in viscous fluid form on the surface of the material and drying the xanthate so as to cause the superficial fibres to adhere to the surface. With certain materials such as jute, the alkalinity of the coating composition affects the material undesirably as regards color, strength and durability or affects the contents of a'sack or the like made from the material.

It has also been proposed heretofore to coat jute textile materials with rubber or cellulose derivatives which are soluble only in organic solvents, but such substances interfere with the reuse of the waste textiles because such coating compositions can be removed only by means of organic solvents, the cost of which is prohibitive in most cases. If such compositions are not removed, the papers and textiles made from the waste cannot be properly or uniformly bleached, dyed, softened, or otherwise treated with aqueous solutions because the rubber and cellulose derivatives alter the permeability of the textile materials.

It is an object of the present invention to provide means for laying the surface hairs or fibres on textiles and to prevent the shedding of such fibres.

It is a general object of the present invention to provide for the treatment of textiles, in particular textiles formed in whole or in part of jute in such a manner to improve the appearance and duramanufacture of sacks, bags, packages, container liners and the like.

It is a further specific object of the invention to provide a composition for the finishing of textiles, in particular jute textiles, so that the finishing material will not interfere with the recovery and. reuse of the treated textile.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The present invention therefore provides for the treatment of textiles, in particular jute textiles, with an aqueous dispersion of a cellulosic material such as a compound of cellulose, the dispersion having a pH value less than 8.0, that is, a composition which is only slightly alkaline 'or neutral or acid in reaction, whereby the composition does not adversely affect the strength of the textile material and does not impart an objectionable color to the jute as a result of excess alkalinity present in said composition, thereby enabling the waste material to be reused without the necessity of removing the cellulose compound deposited thereon.

In a preferred embodiment, a jute textile is treated with a dispersion of cellulosic material,

the dispersion being within the zone of litmus neutrality. It is to be understood that the expression textile includes material in the form of yarns, threads, cordage, as well as fabrics of all kinds. The invention has particular reference to the finishing of textiles made in whole or in part of jute fibres. 7

It has now been found that jute is not adversely discolored by liquid compositions having a pH value of less than eight. When jute fabric is treated with a cellulosic material dissolved in acid solution, i. e., pH less than 7, the acid does not ordinarily discolor or damage the jute as the time of contact of acid with the jute is relatively short. The cellulosic material is immediately coagulated on the jute after application, and the acid is promptly removed, as by washing or neutralization.

For forming suitable finishing compositions by dissolving the cellulosic materials in dilute acids,

fected by prolonged contact of the cellulosic ma- 1 terial with the acid. Cellulosic materials are usually diflicultly soluble in most acids, and hence acids are not as desirable as the dispersing agents as salts, Water and various dispersion media of pH less than 8.0 herein described.

In selecting acids suitable for dissolving cellulosicmaterialsfor treating jute it isonly nee-.-

is possible to quickly and easily determine whether or not the acid is of concentration sufficient to deleteriously affect the jute material to;

be treated. Most acids (in a dilute condition) do not adversely affect the jute, but it is obvious that strong acids such as sulfuric or nitric acids, particularly when in concentrated. solution, are unsuitable for use in treating. jute, This. is.-

readily determined by placing-a sample of jute in a concentrated solution or sulfuric acid-for 2 minute according to the a'bove test and-observing the harmful effect of sucs cnsem e n; It is quite possible to use sulfuric 'acid of diluted concentrations successfully to on the jute.

dissolve certain cellulosic materials and then treat jute therewith withoutv deleteriouseii'ects.

such as parchmentizing or discoloring. the jute. However, the invention is applicable .to textiles V fabricated from other cellulosic fibres and which may be mixed or combined with jute, in particular, natural-occurring vegetable fibres, such as flax, hemp, cotton, wood or the like from which sacks and other-containers may be formed for use in the packaging .arts. In particulanthe present invention provides a method oflaying the-surface of nap hairs on textiles made of jute alone and of preventing the shedding of loose jute fibres from such-textiles, withoutweakenv ing'the fibres and without imparting a discolororationthereto. It is to be understood thatin the specification and claims the expression. fsolutionf is meant to include a true solution and/or a colloidal solution.

The invention accordingly comprises .a composition of matter possessing the characteristics, properties and the relation of components; a process comprising the several steps and the relation of one or more'of such steps'with respect to each of the others, and the product possessing the features, properties and the relation of con- 7 stituents which are exemplified in the following detailed disclosure andthe scope of the invention will be indicated in the claims. In recent years the hydrogen ion concentration method of determining" acidity, alkalinity and neutrality has come into use with the provision of delicately adjusted indicators to make possible more accurate determinations than heretofore available with the aid of litmus and the like. According to authorities, litmu indicates neutrality between a pH of 4 or 5 on the one hand (acid side) and a pH of 8 on the other hand (alkaline ide) Within these limits there exists what may be termed a neutral zone defining neutrality as originally'expressed in terms of litmus.

In the treatment of jute according to the present invention there may be employed, as a class, cellulosic material which are soluble in dilute acids, water or alkali solutions of pH less than 8; preferably within the range of litmus neutrality. The cellulosic materials comprise cellulose per se, or cellulose derivatives as a class such for example as cellulose ethers and cellulose esters which are soluble in aqueous solutions having a pH below 8. The cellulose esters may'comprise l for example, low-esterified cellulose esters as cellulose acetate, cellulose nitrate, cellulose formate,

cellulose butyrate and mixed cellulose estersv which are soluble in "water or dilute aqueous acids, alkali. or saltv solutions'b'elow pH .of. 8.0.

Cellulose ethers may comprise, for example, alkyl ethers, hydroxy-alkyl ethers, carboxy alkyl ethers, and mixed alkyl hydroxy-alkyl ethers of cellulose such, for example, as methyl cellulose,

ethyl cellulose, propyl cellulose, hydroxy-ethyl cellulose, methylhydroxy-ethyl cellulose, cellulose benzyl sulfonates, and the like. Mixed cellulose ether-esters may be employed such as hydroxy ethyl cellulose acetate, methyl cellulose nitrate, and the like. The carboxy-alkyl cellulose ethers which maybe employed comprise cellulose glycolic' acid ether and it homologues, and alkali metal-salts of the carboxy-alkyl cellulose ethers.

Theremay be, employed cellulose inits various forms which may be dissolved in aqueous solutions of lessthan pI-I of 8.0, for example, alpha cellulose, beta cellulose,- oxycellulose, lignocellulose, degraded forms of such varieties of cellulose which may be produced by degradation and/or oxidation as by treatment with heat, acids, alkalies, and the like, which treatment re-.. sults in producing a cellulose which is soluble in aqueous solutions having a pH below 8. 0.

The various cellulosic materials employed in the invention maybe dissolved in a variety. of

solvents such as dilute acids, alkalies or saltsdispersedordissolved inaqueous media suchaswae.

iodides, alkali metal perchlorates, zinc chloride,

and acids such'as hydrochloric,sulfuric, formic and phosphoric acids in aqueous solutiononin' admixture with the Varieus salts, and sufiiciently dilute to prevent the. solution from dissolving the, I

jute, preferably less than 62% concentration. f

Cellulosic material dissolved in alkali solution is employed. in treating jute only after the. pH

. of the solution has been adjusted tolessthan pH of 8.0.; When saltsor acids are employed, the

cellulosic, material is dissolved in suchsolventsat elevated temperatures andthen cooled to room temperature or slightly below 20 C. beforebeing usedfor treating the jute.

In the no w preferred embodiment of; the in vention, the water-soluble cellulose ethersv which are Ql b ei s bstantia vneut a aqu u 0.111:

1 pH ap roximately s. .wate ...ap-..

pear to, offer many. advantages over other cellu; rlose c mpound i ereaspn hat the cellul se. compoundon the jute waste material. may be readily removed before reusing the-jute fibres re.-. covered therefrom inthe textile and paperarts By; way of illustration but not by way. of limitw ing the invention. the following exam les will be given:

Example, l

A fabricmade oi -jute waspassed througha composition comprising a coldusolutionof apH of 7.0, formed by dissolving 5 parts of water-- s-c-luble'ethylcellulose in parts of wa te'r. The

passing the fabric through squeezerolls fora secend time the rollers lay the nap andthe-cellulose ether bindsithev nap fibres to the fabric; thus producing-a product having a relativelysmoothsurface.

7 Example If Jute bagging was treated in accordance with the steps of the process set forth in Example I, namely, the'bagging was padded with a cold solution comprising 3 parts by weight of alpha cellulose dissolved in a 59% solution of Zinc chloride by heating to between 60 and 80 C. for sufficient period of time to dissolve the cellulose. The solution of Cellulose and zinc chloride was found to have a pH approximately of 1.5. After padding the jute bag for a periodof time sufficientto impregnate the material, the padded material was immediately passed into cold watrto partially coagulate the alpha cellulose thereon; then through hot water to further coagulate the cellulose on the bagging. After coagulation of the cellulose the material was washed to remove any excesszincchloride and thendried at slightly elevated temperatures. The bagging had an improved hand and less tendency to nap.

Example III A jute fabric in the form of a large roll was treated by passing the material in a continuous manner through a bath comprising an emulsion of hydroxy ethyl cellulose. The emulsion is prepared. by first dissolving 4% by weight of alkalisoluble hydroxy ethyl cellulose in an aqueous solution of 3% sodium hydroxide, and then dispersing this solution in a mixture comprising equal proportions of Stoddard solvent (naptha) and sulfonated castor oil. While this mixture is being agitated there is introduced suflicient 5% aqueous acetic acid solution While stirring to adjust the pH to between 7.5 and 8.0. The jute was then padded with this emulsion immediately after it had been prepared, as these types of emulsion are not stable for long periods of time and must be used as they are made up. After padding, the cellulose ether was coagulated thereon by passing the fabric through a dilute aqueous solution comprising 5% hydrochloric acid, thereafter passing the fabric into water to remove the excess acid, then Washing and drying in the usual manner. The above treatment did not produce objectionable discoloration in the jute fibres. The composition lays the nap and binds the loose fibres.

Example IV Ordinary cotton was purified and dewaxed in the usual manner, then dried and comminuted to a fine powder. A padding composition for jute bagging was prepared by dissolving 5% of the cellulose in a 66% solution of hydrobromic acid at about 3 C. The acid concentration was then carefully adjusted to about 60% by addition of sufficient water. Jute fabric was then treated by padding with the above composition, then passed into hot water at about 65 C. to coagulate the cellulose on the fabric and to remove the acid. The fabric was then passed through squeeze rolls to bind the loose fibres to the fabric. The acid may be recovered and reused. All parts are by weight, based upon the acid. The jute fabric was not discolored or damaged by the composition during treatment.

The composition may be applied by spreading, brushing, dipping or otherwise to the surface of the fabric or material to be covered. While still wet, the material may be pressed, rolled or otherwise suitably treated so that the superficial hairs are effectively laid and adhere to the surface. the cellulose compound is then coagulated in a suitable manner and" the material is dried. and The treatment finished in the usual manner. does not produce an objectionable colorationv of the jute fibres. 1 i There may be added to the composition various fillers, loading materials, pigments, dyestuffs,

sizes, dispersion assistants, Wetting agents and agents for fireproofing, waterproofing, preserving, softening, and the like for imparting to the composition or the treated textiles various properties well knownin the art.

Since certain changes may be made in carrying out the above process and in the product, and modifications effected in the composition for practicingv the principle thereof, without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

The present invention is a continuation-inpart ofthe application Serial No. 281,534, filed I comprises the steps of applying to such fabric a textile finishing composition having apH value less than 8.0, said compositioncomprising a coagulable water insoluble alkali soluble cellulose ether dissolved in an alkaline aqueous solvent for the said cellulose ether, said solvent being of an alkali concentration insufficient to dissolve or discolor said jute, and thereafter coagulating said cellulose ether on said fabric whereby the said loose nap fibres are bound to the surface of said fabric by the coagulated cellulose ether.

2. A process for the treatment of textile fabric comprising jute fibres which would be discolored by strong alkalis and which fabric is characterized by having loose nap fibres, which process comprises the steps of applying to such fabric a textile finishing composition having a pH within the zone of litmus neutrality, said composition containing a coagulable cellulose ether dissolved in aqueous solvent therefor, said solvent being of concentration insufiicient to dissolve or substantially discolor said jute, and thereafter coagulating said cellulose ether on said fabric, whereby the said loose nap fibres are bound to the surface of said fabric by the coagulated ether, without substantially discoloring said fabric.

3. As a new product, textile fabric comprising jute, dressed with a water insoluble cellulosic body adhering to the fibers'thereof and free from stains which would be caused by the treatment of said textile material with an alkaline solution having a pH above 8, said product being substantially free from loose nap jute fibers.

l. As a new product, textile fabric comprising jute, dressed with a cellulose ether adhering to the fibers thereof and free from stains which would be caused by the treatment of said textile :REFERENJCES CITED 'Thefollowingreferences' are of record'in the file 0f this*patent: V 1

Number Number 8 UNITED STATES PATENTS Name Date a Bolton Ju1y'20, 1937 Webb .May 4, 1926 Hardy Nov. 8, 1938 Schorger June, '14, 1932 Lilienfeld June 20, 1916, Neugebauer et a1. Oct. 4, 1938 Hentrich-et a1 Jan. 31, 1939' 'Whitehead June 27, 1939 Powers Sept, 24, 1940- Dreyfus et' a1 Mar. 13, 1934 Reichel et a1. 1 Sept. 5, 1939 "'Bock'et a1. Feb. 29, 1944 FOREIGN PATENTS Country Date Great Britain Feb. 25, 1931 Great Britain 1940 

